  Calculation method for selection of slewing bearing (turntable bearing)
Calculation method of static reference loads Fa’ and M’
Single-row four-point contact ball
Single-row four-point contact ball type slewing bearing selection calculation is carried out according to two cases of bearing angle 45° and 60°.
I, a=45° Ⅱ, a=60°
Fa’=(1.225•Fa+2.676•Fr)•fs Fa’=(Fa+5.046•Fr)•fs
M’=1.225•M•fs M’=M•fS
Then find the above two points on the graph, one of them can be below the curve.
 
Single row cross roller
Fa’＝(Fa+2.05•Fr)•fs
M’=M•fs
 
Double row reducer ball type
For the selection calculation of double-row reducer slewing bearing, when Fr≤10%Fa, Fr is ignored. When Fr>10%Fa, the change of the pressure angle in the raceway must be considered. For its calculation, please contact us.
Fa’=Fa•fs
M’=M•fs
 
Three-row roller type
When selecting a three-row roller slewing bearing, only the effects of axial raceway load and overturning moment are calculated.
Fa’=Fa•fs
M’=M•fs
 
The National Development and Reform Commission issued a new standard for slewing bearingson February 1, 2008.
1. Replace JG/T 68-1999 "Three-row column slewing bearing for construction machinery" by JB/T 10837-2008 "Three-row column slewing bearing for construction machinery and equipment";
2. By JB/T 10838-2008 "Single-row cross roller (cone) slewing bearing for construction machinery and equipment" replaces JG/T 67-1999 "Single-row cross roller (cone) slewing bearing for construction machinery", the new standard cancels the original Appendix 1 "Supplement Series Specifications;
3. JB/T 10839-2008 "Single Volley Slewing Bearings for Construction Machinery and Equipment" replaces JG/T 66-1999 "Single Volley Slewing Bearings for Construction Machinery", the new standard adds overlapping section configuration, Some unused specifications were canceled, and some new specifications were added to 48; the original Appendix A "Supplemental Series Specifications" was cancelled; the performance curve was drawn according to d0≤40, 57HRC, d0≥50, 55HRC.
All three new standards have abolished product quality grading and will be implemented as of July 1, 2008.
 
For detailed information or custom part numbers, please contact us directly.